Metalised polyester films are increasing in popularity for their high-barrier properties in laminated flexible packaging structures. However, poor adhesion of metal to the base polyester film can result in laminate failure, thereby affecting product performance.

Films with high metal adhesion for superior barrier applications in harsh environments are currently available, but they are limited and costly.

As a response, a USA-based company, Flex Films, has engineered a high-barrier metallised polyester film, FLEXMETPROTECT F-HMB.

The film is either untreated or corona treated on the other surface, while metallisation is carried out on the specially treated composite surface. It achieves metal adhesion or a bond strength greater than 1200 gram-force/in.

The adhesion of metal on BOPET base film is the sum of chemical and mechanical adhesion. The proprietary surface treatment of the base film allows increased levels of chelation or reaction with the metal being deposited, thereby resulting in a much better adhesion profile.

“The specialised surface treatment comprises materials with unique and enhanced properties, thereby leading to much enhanced mechanical bonding. It took us almost 18 months to engineer this film,” said Dr Steven J. Sargeant, General Manager, Technology, at Flex Films.

The film offers class-leading adhesion to metal under most aggressive environmental conditions; improved scuff, scratch and craze resistance, thereby improving yields up to four percent and offering robustness in processing and performance for converters; compliance with EU and FDA regulations for food-grade applications; and cost-effectiveness.

FLEXMETPROTECT F-HMB film finds extensive use in liquid packaging, stand-up pouch applications, bag-in-box products, chemical packaging, pharma packaging and hot-fill applications up to 80°C. The film is available in 8 to 50-micron thicknesses.

Flex Films is the global film manufacturing arm of India’s largest multinational flexible packaging materials company, Uflex Ltd.


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